The present invention is directed generally to dispensing systems, and more particularly to an implantable manually-actuated micro-infusion pump system for dispensing prescribed dosages of a fluid medicament within the human body.
Implanted manually-actuated micro-infusion pump systems are advantageously employed when specific dosages of a medicament are to be administered within the human body at various times over an extended time period, as in the treatment of diabetes, cancer, pain, and many other diseases.
Typically, in the treatment of diabetes a dispensing system comprising a combined pump and medicament reservoir system is subcutaneously implanted in soft tissue close to the delivery site, such as over the peritoneum and abdominal muscles, and a catheter is utilized to deliver insulin to the site. Alternatively, the reservoir is implanted remotely from the site and connected to a pump system by means of a flexible catheter. When insulin is required actuation of the pump system is accomplished by the patient applying pressure on the skin surface overlying the pump.
For effective treatment it is generally required that the medicament is dispensed in measured dosages. Consequently, it is necessary that a known volume of medicament be dispensed with each actuation of the pump system, so that the user can determine the total dosage dispensed by the number of pump actuations. In the case of insulin treatment of diabetes, for example, the pump system may administer 0.1 milliliters of insulin with each actuation, so that a typical post-meal dosage of 0.6 milliliters, for example, may be administered by six (6) successive actuations of the pump system.
One drawback of previous implantable manually-actuated micro-infusion pump systems has been their susceptibility to externally applied pressures, causing them to inadvertently dispense doses, or to dispense inaccurate doses, or to permit uncontrolled flow of medicament into the body. Moreover, such pump systems must be sealed against body fluids, must hold a sufficient quantity of medicament so as to avoid the need for frequent refills, and must be refillable to preclude interruption of the medicament schedule. Furthermore, such pump systems must be physically small so as to be readily implantable without unnecessary disturbance to the body.
The present invention is directed to a manually-actuated micro-infusion pump system which satisfies these requirements, and is convenient to operate and economical to manufacture.
Accordingly, it is a general object of the present invention to provide a new and improved manually-actuated implantable microinfusion pump system.
It is a more specific object of the present invention to provide an implantable manually-actuated micro-infusion pump system which provides increased protection against inadvertent actuation from externally applied pressures.
It is a further object of the present invention to provide a new and improved manually-actuated implantable micro-infusion pump system which provides a high degree of metering accuracy and is compact and economical to construct.